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My 08 E350 with 155000 miles battery light just came on, the battery was replaced 60 days ago. Hooked up the voltmeter and it read 11.6 with the engine not started. Cranked the engine, nothing, voltage stayed the same after running the car for 5 mins. 99% sure its the alternator. Question, anyone used Bosch or Duralast replacement and if so, what voltage did you get, 150 amp or 180 amp? Which one is the best?
Before you replace that alternator, check the Voltage Regulator. That easily replaceable part is usually the problem of low voltage. Make sure you use only the Bosch brand and not some cheapo aftermarket part.
x2 on VR. That is pretty cheap part, even you have to buy whole assembly, when only brushes are needed.
"Battery light" is low car voltage indication, so with running engine it shows bad charging not battery.
Thanks, so the VR is a common problem? Saw in a post some guy replaced the VR and still had issues, then I read in another that after 150000 miles an alternator usually out. Thanks, will try the VR and keep all posted.
I'll go against the common thinking and say just replace the alternator. Seems like I have read a lot of threads on here in which the VR gets replaced only to have the alternator fail shortly after.
Do it once, do it right.
Can’t seem to find a Bosch VR, most places (pelican parts, eEuro, autohauAZ, FCPeuro) carry only the MB for $115.
Thinking about replacing the entire unit, is there a way to check the VR only? Like I said, the battery was reading 11.6 on the tester and didn’t move when the engine was running.
Last edited by Flexx08benz; Oct 10, 2018 at 05:27 PM.
You can easily pull out the regulator from your alternator. Then compare the brushes to photos of a new one. The MB one is most likely made by Bosch. The price you listed is a good price. Better than anything the dealer will quote you.
Finally got a chance to pull the alternator today and removed the VR. Check out the old compare to what a new one would look like.. Think VR replacement would fix the issue right? Pic of a new VR, Inside the alternator shaft (dirty, broken shavings) Old VR Old VR
I wonder if all the sparking mentioned above might have had a detrimental effect on something other than the brushes themselves. Or if all the carbon dust that has been shed inside the alternator might be bad for things like... I don't know... shaft bearings, and such.
Yes, this is me standing behind my original statement of "just replace the whole alternator". You've already done the hard part: taking it out.
Ordered the Bosch VR from FCPeuro and installed tonight, battery light went out and battery seemed to be charging. 🙏🏾 Issue is fixed. Thanks for all the help Benz fam!!!
When VR is basically only wearable on the alternator, there is more that can fail.
But you are saying that new VR fixed the issue for a month?
The dirt on previous pictures indicate that VR might be rubbing against moving parts, what grinds it prematurely.
The easiest way obviously is get whole new alternator, but I would still investigate the old one.
Both ***** are wearing unevenly, one seems to be making 100% contact and the other doesn’t. The shaft where the ***** contact are displaying different discoloration also. Will take pic tomorrow. Alternator off so I’ll get it tested tomorrow.
Sounds like the bearing may have worn out. I got the cheap one from Autozone for my 2008 E350 4matic. Used the 20% off coupon and it was about $172 after I got my $40 core back. I just got the cheapest 15710 on the theory that the one they carry in stock is the more likely one and they all have a lifetime warranty anyway. I think they went up about $2 in price since the last time I got it. I think on previous models the type of alternator used to matter but that doesn't seem to be the case with the post face lift. I took a picture of my old one anyway and it had a part number of A0131545602. I knew mine was bad because it smelled burnt and was making noise. Mechanic said the bearings were probably shot causing the winding to short out, it was all black instead of copper looking.
On the shaft one of the groves where the prone rubs on is darker than the other or should I say doesn’t show the copper finish.
Not getting any noise from the alternator and the bearing seems fine, no movement that I can tell. After tomorrow I’ll know what to do.
That's alternator math. I didn't think it was worth it to swap the regulator considering the price of a new one and you have to remove the alternator anyway to replace the regulator. Plus mine smelled burnt so I knew it probably wasn't the regulator anyway. Plus everyone pretty much has a lifetime warranty on their alternators so there was no point getting it from FCPeuro as theirs was $300 and with a local store, it's easy to swap if/when it goes bad.
Got the alternator tested today, as expected it’s not charging. Weird thing is I re-enstalled the alternator so I could drive the car to the shop and for 10 minutes it began charging up to 14.2. then it dropped to 12.0 before the light came on.
Can I install a 180 AMP if the car came with a 150 AMP? Would it damage anything? Both are comparable and the vin# verified it at FCP.
Last edited by Flexx08benz; Nov 27, 2018 at 11:38 AM.
You can never have too much amperage when it comes to alternators; therefore, you never have to worry about choosing an alternator with too high of a rated output. Here’s why:Amperage is basically the amount of electrical current your alternator can supply. And it basically operates off of supply and demand. That is, your alternator will only supply the amount of amperage a particular component demands—and no more. So high-output alternators will not harm your components or charging system, no matter how high you go with the amps.
I also looked into if your OEM charging wires need to be thicker gauge, and based on my research you dont need to upgrade. There is a neat chart below
e350forme, thanks for the insite, I was thinking it wouldn’t be an issue since all the systems using the out put voltage would regulate what is needed. Really appreciate the research and link included. 👊🏾
e350forme, thanks for the insite, I was thinking it wouldn’t be an issue since all the systems using the out put voltage would regulate what is needed. Really appreciate the research and link included. 👊🏾
thanks! This is the first time I ever actually helped someone on this forum haha! You can always click THANKS and I will have my first thanks!
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